Modeling of the spectral response of Al_xGa_1−xN p-n junction photodetectors

¹ LPMM, Université Hassan II, Faculté des Sciences Aïn Chok Km 8, route El Jadida, BP 5366, Maârif, Casablanca, Morocco
² ETSI Telecommunicacion, Universitad Politecnica de Madrid, 28040 Madrid, Spain
³ CRHEA-CNRS, parc Sophia Antipolis, rue Bernard Gregory, 06560 Valbonne, France

Corresponding author: bouhdada@facsc-achok.ac.ma

Received: 26 July 1999
Revised: 1 January 2000
Accepted: 25 April 2000
Published online: 15 July 2000

Abstract

We propose to model the spectral response of p-n junction photodetectors based on gallium nitride and related AlGaN alloys. The model is based on the resolution of the differential equations that govern the excess carrier variation in each layer of the photodiode taking into account all the physical parameters, in particular the presence of deep trap levels in the forbidden gap. We notice that the theoretical results are in good agreement with the experiments. We have also analysed the effect of the recombination velocity at the illuminated surface, as well as the impact of the thickness and the doping density of the p-type layer (illuminated zone) on the spectral response magnitude.